Exercise throughout the lifespan

1. Exercise throughout the lifespan Text pages 639-650

2. Lifespan • Infants • Children • Adolescents- Puberty • Adults • Aging

3. Infants

4. How much exercise do babies need? • Parents are often concerned about the amount of exercise they should engage their baby in on order to enable successful motor development • The response is generally that play, cuddling, feeding, bathing etc is enough activity for a normal baby, and that there are so many different rates of development, there is no need to be concerned about their baby being “normal”

5. Recommended activities for Infants (Birth to 12 months) • Engage your infant in some activity every day. This includes setting up safe areas for the infant to play in, playing games with them, and carrying them to different environments to explore. Do not keep infants in baby seats or other restrictive settings for long periods of time. • To encourage your infant to be active, try the following: • Lay your infant on a blanket on the floor with a few toys • Provide brightly coloured, easy-to-grasp toys that can be squeezed or have different textures to encourage reaching and grasping • Place the infant on his tummy facing you, encourage him to lift his head and kick his legs • When the baby is learning to roll over, hold a favourite toy just out of reach to motivate him to keep trying • Play peek-a-boo or patty-cake; help move your child's hands so she learns the motions • Carry the child to a new environment, set her down, and let her explore (be sure the area is baby-proofed)

6. Recommended activities for Toddlers (12 to 36 months) • As walking skills progress, toddlers have a seemingly unending supply of energy. Encourage them to use it all! Toddlers should accumulate at least 30 minutes of structured physical activity each day. Do not keep toddlers in baby seats or otherwise inactive for long periods of time. • Try the following: • Bounce, throw, and chase balls to develop hand-eye coordination (use soft balls that won't break anything) • Dance to music and follow-along songs (think: Hokey-Pokey) to promote body awareness and balance • Play Simon Says and Follow the Leader • Provide safe, sturdy objects to ride, push, pull, balance on, and climb • Make chores into games that kids can help with, for example: • During dinner preparation, have him carry something that won't break or spill to the table • On laundry day, have her throw her dirty clothes into the laundry basket • Encourage stair climbing, which develops leg muscles and coordination, but do so only on carpeted steps with an adult right behind to prevent falls

7. Recommended activities for Preschoolers (3 to 5 years) • As kids gain more strength and balance, it is easier for them to accumulate the recommended minimum of one hour of physical activity each day. Some suggestions: • To promote balance, help the child walk along a line on the ground, or along a sidewalk curb when there are no cars around • Lay out objects to create a maze or tell a child to run around a tree and back, providing vigorous exercise plus mastering turns and balance • Around age 3, children learn to hop and are ready for hopscotch; draw paths that require the child to hop first on one foot, then the other. This promotes balance and strengthens leg muscles • Around age 4, kids learn to skip; practice skipping with them across the yard, or work it into a game of Follow the Leader • Provide safe objects to ride, push, pull, balance on, and climb • Emphasize fun, not competition. Preschoolers lack the social and cognitive development for organized team sports, which can leave them frustrated and block later interest in sports.

8. Children The impact of growth and potential for sports conditioning

9. Boys Girls Decelerated growth Peak height velocity Accelerated growth Decelerated growth Adolescent growth spurt Note the sex differences here

10. Growth • Boys and girls of the same age are generally similar in terms of height, weight, strength etc until puberty • The increase in size over childhood is the most important factor in determining the changes in their response to exercise • Biological age may not parallel chronological age

11. Increases in size • In females • Muscle mass increases 7 kg  23 kg • % Body fat increases 16%  23% • In males, between the ages of 6 and 16 • Lungs grow which increases total lung capacity from 1937  5685 ml • Heart grows in weight from 95g to 258 g • Muscle mass increases

12. Aerobic factors • Heart rates in children may reach 220 or even 225 before puberty, but tend to fall to around 200 in their late teens, so the coach should not worry on finding such high rates in exercising youngsters. • Children also breathe faster than adults, reaching 60 breaths/minute compared to 40/minute in adults doing equivalent exercise. • Compared to adults, children need to breathe more air to get the same amount of oxygen, i.e. their ‘ventilatory equivalent for oxygen’ (the number of litres of air to gain one litre of oxygen) is higher. This is wasteful of energy and body water (in the breath).

13. Energy systems • Muscular concentration of ATP is similar in children, adolescents, and adults • The total reservoir of high energy phosphates is lower in children because of their smaller muscle mass relative to structure. • In exercise, depletion of high-energy phosphates occurs at similar rates for children and adults. • Boys' anaerobic performance increases with age from childhood to adulthood. When related to body mass, the anaerobic performance of an 8 year-old boy is about 70% of an 11 year-old. • Girls' anaerobic performance also increases from childhood but appears to reach a maximum value during the teen years.

14. Anaerobic Capacity • Children have a distinctly lower anaerobic capacity compared to adolescents and adults. • Low levels of male reproductive hormones • low glycolytic capacity • lower lactate production • decreased buffer capacity • decreased rates of glycolgenolysis • lower lactate threshold

15. Thermoregulation • Children are not as effective in dissipating heat as adults: • produce more heat relative to body mass • lower sweat rates at rest and during exercise • greater energy expenditure during exercise • lower cardiac output relative to metabolic intensity • rely more on convective heat loss than evaporative cooling

16. Training Considerations Even when controlling for maturation, it is clear that children can adapt to endurance training Physiologic changes in children resulting from training and growth and maturation

17. Benefits of exercise for children • Caloric balance • Stimulates growth hormones • Growth Hormone • Mechanical stresses (overload) triggers musculoskeletal growth • Hypertrophy of muscle • Metabolic efficiency

18. Adolescents Pubertal growth spurt

19. Growth and Development The most rapid increase in height and weight occurs during puberty, and is referred to as the pubertal growth spurt The most rapid rate of growth occurs during the adolescent years, and is referred to as the peak height velocity (PHV). Girls tend to be slightly taller and heavier than boys from years 2-10, and PHV occurs 2 years earlier in girls than boys

20. Assessment of Maturation As children mature at different rates, chronological age is not a good gauge of physical development or maturation. Tanner stage of sexual maturation

21. Fat free mass • One of the major changes during puberty is the increase in body fat in females • Muscle mass represents 53% of the weight of an average 17 year old male; but 42% of that of a 17 year old female • This is a result of the respective sex hormones

22. Aerobic capacity • Muscular concentration of ATP is similar in adolescents, and adults • Adolescents have significantly lower muscle glycogen stores than adults and also are less capable of generating ATP. • Young people do not have the same capabilities as adults to perform strenuous exercise for periods between 10 and 60 seconds. • Gender-related differences are minimal prior to puberty. However, during adolescence boys become significantly better anaerobic performers than girls, an advantage that is retained for the remaining years.

23. Male Female Laboratory Measures Of Physical Fitness In Children Aerobic Capacity Note altered trends when body mass is considered

24. Strength training • Resistance training in prepubertal subjects tends to cause increases in strength without increases in muscle size • 30-40% gains in strength following an 8-12 week program (Payne, Morrow, Johnson., & Dalton, 1997) • Resistance training effects can be found in young, adult, and aged populations. • Girls have the potential to improve more than boys. [They start from a lower status.]

25. Precautions with strength training • Epiphyseal injuries- epiphyseal plate (point from which bones grow) fuses resulting in stunted growth as bones cannot grow anymore • Adolescents should avoid competitive weight lifting, power lifting, body building, and maximal lifts until they reach physical and skeletal maturity (~ 17 females and 18.5 males) • These are mostly caused by maximal lifts, improper technique and improper supervision • Adolescents should use lower weights and higher reps rather than 3 or 4 reps of a 80-100% max weight

26. Adults The majority of the acute and chronic adaptations to exercise that we have studies apply to adults 20-50 years of age

27. Aerobic capacity • Vo2 max decreases by 8-10% per decade after 30 • Those that exercise can halve the usual decline that is expected with age, ie. 4-5% per decade loss of vo2 max

28. Mid life changes • Menopause- cessation of menstruation in women – av age = 51-Regular exercise during menopause is known to decrease the frequency and severity of hot flushes • Andropause may or may not actually exist as a clinical phenomenon. Its proponents claim it is a biological change experienced by men during their mid-life  steady age-related decline in testosterone levels in men, since a man's reproductive systems gradually decline with age, but do not stop working altogether in mid-life, as a woman's do.

29. Older Adults

30. Defining Aging • A manifestation of biological events that occur over time. • The natural life span is suggested to be the age of 85. • Life expectancy is the average, statistically predicted length of life for an individual. • 71 years for men of developed countries • 78 years for women of developed countries • It is estimated that in the near future 50% of all deaths will occur after the age of 80 years

31. Successful Aging • Requires maintenance of enhanced: • Physiologic function • Physical fitness • Components of successful aging • Physical health • Spirituality • Emotional and educational health • Social satisfaction

32. Physical Activity and Aging • Physical activity reduces the impact that “normal aging” has on: • Blood pressure- normal aging= BP increases, especially with artherosclerosis • Body composition- 10% reduction in BMR  up to age 65 and further 10% after. This is what leads to an increase in body fat if portion sizes/ exercises are not altered • Muscle mass- normally a 3-5% loss in each decade after 25. resistance exercise limits loss of muscle and strength • Bone mass- normally decreases • In females -2-3% decline after 30 = 20% by 65; 30% at 80 • In males - 1% per year after 50 = 10% by 65, 20% by 80 but the decrease can be limited by resistance exercise

33. Effects of exercise and age on select body systems, simplified

34. Effects of exercise and age on select body systems, cont’d

35. Maximal Oxygen Uptake (VO2max) Decreased VO2max Aging associated decreases in maximal cardio-respiratory endurance  Cardiovascular function  Ventilatory and pulmonary function  Cardiac output  VE/Q mismatch  Work of breathing  Blood volume  Stroke volume  Respiratory muscle strength/endurance  ejection fraction  Lung compliance and elasticity  ventricular filling Closing volume  myocardial compliance and elasticity • VO2max decreases 8-10%/decade after age 30 • VO2max can be equally improved with training in the elderly as it is in youth

36. Pulmonary Changes with Age Structural & functional changes to the pulmonary system with age

37. Musculoskeletal System By age 90, 32% of women and 17% of men will have sustained a hip fracture. Regular physical activity can decrease the rate of age-related bone mineral loss Adolescent male Adolescent female 30 year old - active 30 year old - inactive % Decrease in bone mineral

38. Muscle Trainability Among the Elderly • Regular exercise training retains body protein and blunts the loss of muscle mass and strength with aging • Older people are equally as responsive to resistance training as young people

39. Aging and Joint Flexibility • With advancing age, connective tissue becomes stiffer and more rigid, which reduces joint flexibility • Regularly moving joints through their full range of motion increases flexibility by 20 to 50% • Osteoarthritis is common degenerative joint disease found among older adults. It is caused by the wearing down of cartilage which results in 2 bones rubbing against each other pain and inflammation

40. Aging and Endocrine Changes • Endocrine function changes with age, particularly the pituitary, pancreas, adrenal, and thyroid glands (reduced thyroxine is responsible for the lowered BMR) • Impaired glucose tolerance means that body is not able to release right amount of insulin to deal with blood glucose levels and coordinate the storage/usage glucose/glycogen. This can lead to type 2 diabetes

42. Aging and Cardiovascular Function • Maximal oxygen uptake ( O2max) declines steadily after the age of 20 • A slower rate of decline occurs for individuals who maintain an active lifestyle that includes regular aerobic exercise training • Physical activity, however, does not entirely offset aging’s effect on O2max

43. Aging Response to Exercise Training • For the healthy elderly, exercise training enhances the heart’s capacity to pump blood and increases aerobic capacity to the same degree as in younger adults

44. Summary Although exercise is beneficial throughout the lifespan there are considerations for the safety and effectiveness of exercise at different life stages